OBJECTIVES: This study aims to compare the impact of two different sources of resource use, self-report versus routine registrations, on incremental cost-effectiveness ratios (ICERs). METHODS: Data were obtained from a cost-effectiveness study performed alongside a two-year randomized controlled trial evaluating the effect of an INTERdisciplinary COMmunity-based management program (INTERCOM) for patients with chronic obstructive pulmonary disease (COPD). The program consisted of exercise training, nutritional therapy, education and smoking cessation support offered by community-based physiotherapists and dieticians and hospital-based respiratory nurses. Data on caregiver visits, hospitalizations, diet nutrition, devices, (un)paid help, travel expenses and time lost from paid work over the two-year period were collected using a cost booklet. In addition, data on hospital admissions and outpatient visits, visits to the physiotherapist, dietician or respiratory nurse, diet nutrition and outpatient medication were obtained from hospital- and billing records and local pharmacies. The cost per QALY was calculated in two ways, using data from the cost booklet or registrations. RESULTS: In total 175 patients were included in the study. Agreement between self-report and registrations was good for hospitalizations (r=0.96), diet nutrition (r=0.91) and physiotherapist visits (r=0.89), but above 0.58 for all other types of care. The total cost difference between the registrations and the cost booklet was €464 with the highest difference for hospitalizations 386 euro. Based on the cost booklet the cost difference between the treatment group and usual care was €2,444 (95% CI:-819-5,950), which resulted in an ICER of €29,100/QALY. For the registrations, the results were €2498 (95% CI:-88-6084) and €29,390/QALY, respectively. No differences were found in the cost-effectiveness planes and the acceptability curves between the two methods.CONCLUSIONS: This study showed that the use of self-reported data or data from routine registrations effected within group costs, but not between group costs or the ICERs.